Yamini Karanam, 26, was having brain surgery for a suspected tumour when she discovered her “evil twin sister”.
After waking up from the procedure the PhD student, at Indiana University, US, was shocked to learn of the “teratoma” – her embryonic twin with bone, hair and teeth.
Yamini Karanam only realised something was wrong in September last year when she started experiencing trouble taking in what she was reading.
She told NBC: “Problems with reading comprehension, listening comprehension. If a couple people were talking in a room, I wouldn’t understand what was happening.”
After going to several doctors she became more and more frustrated with their contradictory diagnoses so eventually her own research led her to Dr Hrayr Shahinian at the Skullbase Institute in Los Angeles.
Dr Shahinian has developed a minimally invasive way of reaching deep into the brain to extract tumours.
He used fibre-optic technology with digital imagery and only cut half an inch into Ms Karanam’s brain for an endoscope to reach in and chisel away at her tumour.
Instead of panicking when she woke up and learned what was causing her all the trouble, Yamini Karanam lightheartedly called the tumour her “evil twin sister who’s been torturing me for the past 26 years”.
Dr Shahinian said: “This is my second one, and I’ve probably taken out 7,000 or 8,000 brain tumours.”
Yamini Karanam is expected to recover in just three weeks.